I set 2 sticks of unsalted butter on the counter for 45 minutes. The kitchen was cool on that damp October day. A finger press should leave a dent without sliding through. A thermometer should read about 65°F. Shiny, sweating sticks are too warm, so chill them 10 minutes.
Cut the butter into tablespoon pieces and drop them into the mixer bowl. Beat with the paddle on medium for 90 seconds. Stop once it looks smooth and pale yellow. Scrape the bowl once with a spatula. No lumps should remain. Pale butter with a matte finish means air is going in.
Sift ¼ cup powdered sugar over the butter. Mix on low for 30 seconds. A slow start keeps a white cloud from puffing out of the bowl. The mix should look like thick, matte frosting with no dry streaks. Scrape the bottom edge once where sugar hides.
Drop the speed to low. Pour ¼ cup honey down the side of the bowl in a thin stream over 20 seconds. Honey at room temperature blends best. Honey that pools and a slick, split look mean the butter runs warm. Chill the bowl for 10 minutes, then beat again on medium until smooth.
Add 1 scant teaspoon cinnamon, ½ teaspoon vanilla, and ⅛ teaspoon salt. Beat on medium-high for 90 seconds, scraping the bowl twice. Stop when the butter looks light and holds a soft peak. The color shifts from yellow to pale tan with brown flecks. A dull, heavy look means it needs 30 more seconds.
Smear a bit on a warm roll. Taste for cinnamon and salt. Add a pinch more cinnamon and beat 10 seconds when the spice feels shy. Cold bread hides flaws, so warm the roll for 10 seconds first. My brother-in-law ate three spoonfuls straight from the bowl and said it needed no changes.
Scoop the butter into a 1-cup ramekin, or spoon it onto parchment and roll it into a log. Chill 20 minutes. Serve it cool but spreadable, at about 60°F. A finger press should leave a clean dent, not a smear. Wrap the log in a second layer of parchment for clean twisted ends.
